Phosphorus (P) is a vital limiting nutrient element for plant growth and yield. In Morocco, the natural phosphate rock extractions generate significant amounts of phosphate wash sludge (PS), which could be reused productively, thus creating another added value for farmers. The present study aimed to demonstrate the combination effect of soil amendment by two different PS concentrations (1% and 5%) associated with three phosphate-solubilizing bacteria (PSB) consortia (C1, C2, and C3), isolated from phosphate mining sludge, on plant growth and nutrient uptake in tomato seedlings (Solanum lycopersicum). The results obtained showed that this bioformulation significantly improved P solubilization and plant growth compared to control conditions. Of all the combinations, C3-inoculated soil amended with 5% PS was the most effective in significantly improving plant height and dry and fresh biomass of shoots and roots. P solubilization and its availability for tomato seedlings uptake were maximal with the bioformulation (C3 + 5% PS). This latter enhanced P and potassium (K) uptake by 27.89 and 38.81% in shoots and 38.57% and 74.67% in roots, respectively, compared to non-inoculated soil amended with 5% PS. The highest flowering rate (200 %) was recorded in C3-inoculated soil amended with 5% PS. Supporting these results, the principal component analysis discriminated this bioformulation (C3 + 5% PS) from the other combinations. Our results open up prospects for upgrading phosphate sludge enriched with PSB consortia as a biofertilizer that can be used in ecofriendly agriculture integrated into the circular economy.
Keywords: Biofertilizer; Phosphate sludge; Phosphate-solubilizing bacteria; Plant growth; Solanum lycopersicum.
© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.